Spent Grain Recovery in the Brewing Industry
Common brewery practice involves pumping spent grain at approximately 20% solids by weight to stationary drag type screens for preliminary dewatering, thence to presses and rotary steam tube driers for production of animal feed. In many plants screen and press effluent has been sewered without further treatment, resulting in high protein loss and the potential risk of stream pollution. The fine grain has a higher protein content than that retained by the press and is very desirable in the finished product since price is determined on a protein basis and a minimum must be maintained. Kason Separators have been successfully installed on this application and if no recovery system is in use, amortization is obtained within a few months.
METHOD AND RESULTS
Stationary screen and press effluents are fed to type 316 stainless steel Kason's equipped with 120 mesh screens (0.0046" opening) and recovered grain containing approximately 90% water is fed to the drier with press grain. Stationary screen and press grain in a typical brewery will average 20% protein, whereas Kason recovered fines will average 29%. A 48" Kason will accept feed rates up to 100 IGPM when equipped with a 120 mesh screen. The quantity of solids depends on the stationary screen used and the design of the press.
1. Continuous recovery of valuable high protein fines can be achieved without any operator requirement. The unique 3-dimensional motion imparted by the Kason results in continuous discharge of recovered solids and clarified effluent without any tendency to blind the screen.
2. 120 mesh has been found to be the optimum screen size and particle size distribution is such that even a 325 mesh screen (opening 0.0017") will not yield a significant increase in recovery.
3. While recovering a valuable product, the Kason reduces stream pollution by reducing B.O.D. and suspended solids in the effluent.
4. The addition of Kason recovered protein fines to press grains ensures economically produced high protein grades.
- Type 316 stainless steel construction at all points of material contact.
- Standard discharge spout for both fine grain and clarified effluent.
- Screen opening 120 mesh 0.0046".
- Models available for capacities ranging from 10 to 150 IGPM.
Kason Application Data No: 4